Proposed office tower on the southeast corner of 100 South and Main Street in downtown Salt Lake City. (Deseret news graphic)

SALT LAKE CITY — An Illinois-based developer is proposing to build a 20- to 25-story office tower to complement the city's plans for a Broadway-style theater on Main Street.

Hamilton Partners is working with Swisher Garfield Traub to include a 425,000- to 450,000-square-foot office tower as part of the downtown performing arts center project.

The proposed office tower, which would include shops or a restaurant on the ground level, would be built on the southeast corner of 100 South and Main Street in the site currently occupied by Bennion Jewelers.

Though the office building and theater would be separate, the group's proposal calls for the two buildings to share a galleria-like lobby and entrance..

"We want this building to be very much coordinated with the performing arts center so they look like they're meant to be together," said Bruce Bingham of Hamilton Partners.

Bingham and representatives of Swisher Garfield Traub met Tuesday with the City Council, acting as the Salt Lake City Redevelopment Agency Board of Directors, to provide information and answer questions about the proposed tandem project.

The development team has spent the past 10 months evaluating the feasibility of constructing a state-of-the-art performing arts center capable of hosting first-run Broadway productions. The findings of that study will be presented to the city in about two weeks, though the developers offered a sampling of the findings Tuesday.

Redevelopment Agency officials have been working since October 2008 to negotiate the purchase of the former Newspaper Agency Corp. property between Main and State streets and 100 South and 200 South for the proposed performing arts center. The property is owned by Property Reserve Inc. and Suburban Land Reserve — both of which are development arms of The Church of Jesus Christ of Latter-day Saints.

DJ Baxter, RDA executive director, said the office tower has become part of the theater project because the properties the RDA hopes to purchase are something of a package deal.

"It's become very clear that the two projects, if properly coordinated, could really benefit one another," Baxter said.

The two buildings wouldn't necessarily need to be constructed at the same time, though Bingham said that would be the ideal situation.

According to the developers, design of the theater would take about a year, followed by a two-year construction period. Construction of the office tower would take about three years.

The performing arts center portion of the project is proposed as a 148,000-square-foot, 2,500-seat venue at the site of the former Newspaper Agency Corp. building, 135 S. Main. The estimated $88.4 million theater would utilize 650 parking stalls in the Regent Street parking garage.

Developers also are proposing a mid-block walkway that would connect Main and Regent streets between 100 South and 200 South. The walkway also would align with the Main Street crosswalk in front of the Utah Theater, linking the performing arts center to what's seen as another important part of the downtown arts district. The mid-block walkway would add to the theater's price tag, developers said.

The RDA has spent nearly $825,000 on the feasibility study, an economic impact analysis and strategic communications work.

City officials see the downtown performing arts center as an economic catalyst. The Durham (N.C.) Performing Arts Center, also developed by Garfield Traub Swisher, has generated $27.3 million in annual citywide economic impact since opening its doors in November 2008.

In its first full year of operation, 196 events at the Durham center were attended by more than 340,000 people.

According to the feasibility study, the downtown Salt Lake City theater would host performances on between 138 and 175 days and attract 258,000 to 276,000 patrons per year.